The present disclosure relates to clutches for selectively transmitting torque, and more particularly, a clutch assembly including a mounting ring having a fulcrum for a diaphragm spring and arms for connecting strap springs that bias a pressure plate away from a flywheel.
A clutch assembly is frequently mounted on a vehicle flywheel transmitting driving torque from an engine to a transmission. The clutch assembly generally includes a clutch cover that is fixed to the flywheel and houses a diaphragm spring, a pressure plate, and a friction disc. The diaphragm spring moves the pressure plate relative to the cover and flywheel to engage and disengage the friction disc. As the pressure plate engages the friction disc, the pressure plate forces the friction disc to engage the flywheel and clamps the friction disc between the pressure plate and flywheel. Torque is transferred from the flywheel to the friction disc when the pressure plate clamps the friction disc to the flywheel with sufficient force. A shaft connects the friction disc to a transmission. A thrust bearing mounted on the shaft moves the diaphragm spring to engage and disengage the clutch as described above.
Various improvements have been made to the previously described structure. For example, some clutch assemblies include a series of pressure plates sandwiching multiple friction discs. When the pressure plates clamp the friction discs, the resulting clamped interfaces provide a comparatively larger engagement area that allow more torque to be transmitted by the clutch assembly. Frequently, the original equipment flywheel must be replaced when replacing original clutch assemblies with clutch assemblies having multiple pressure plates and friction discs to provide appropriate axial positioning. One manufacturer has solved this problem by providing an adapter ring between the clutch cover and the flywheel.
Many clutch assemblies include springs (e.g., coil springs or strap springs) that bias the pressure plate toward a neutral position in which the pressure plate is spaced from the friction disc to minimize friction and wear when the clutch is disengaged. These clutch assemblies have diaphragm springs that bias the pressure plates toward the friction discs. The thrust bearing deforms the diaphragm spring to allow the pressure plate to move away from the friction disc. Fulcrums and bosses are frequently provided inside the clutch cover against which forces react created when the diaphragm spring bends.